Suplementação energética e proteica no crescimento folicular e na taxa de prenhez de vacas Bos indicus lactantes submetidas à IATF em estação de monta de 110 dias

Abstract

In beef cows, suckling calf presence and the negative energy balance are the two factors that most impact on the resumption of the postpartum cyclicity, due to the negative effect on the frequency of LH pulses and follicular development. Thus, the association between ovulation synchronization protocols and treatments that increase LH pulsatility are desirable to improve the reproductive efficiency of herds. Alimentary supplementation is a strategy that could be used to anticipate the time of conception of heifers and to increase the pregnancy rate of cows. However, this supplementation in most of the extensive beef cattle production systems in Brazil is made only with the use of mineral salt. Thus, the objective of this study was to evaluate the effect of energy and protein supplementation associated with the FTAI protocol, on follicular growth and pregnancy rate of lactating Nelore cows. For this, the cows were distributed in 2 experimental groups. The Control group (n=169) did not receive supplementation and the Supplement group (n=173) received 2.5kg of supplementation for 26 days during the TAI protocol. It was verified that the supplemented cows had greater follicular diameter, ovulation rate, corpus luteum diameter and pregnancy rate at the end of the breeding season, compared to the control group. Therefore, the energetic and protein supplementation associated with the FTAI protocol increased the fertility of lactating Nelore cows at the end of the 110-day breeding season.